Macrolides

Question 1

What is it indicated for?

Answer 1

Treatment of respiratory, skin and soft tissue infections

Severe pneumonia

Eradication of H.pylori in combination with PPIs and either amoxicillin or metronidazole

Question 2

What is the spectrum of activity?

Answer 2

Relatively broad spectrum of activity against gram-positive and gram-negative

Question 3

How does it work?

Answer 3

They inhibit bacterial protein synthesis

Question 4

What are the side effects of the drugs?

Answer 4

They are irritant causing nausea, vomiting, abdominal pain and diarrhoea

Thrombophlebitis when given IV

Allergies
Cholestatic hepatitis
Prolongation of the QT interval
Ototoxicity at high doses

Question 5

What are the warnings for these drugs?

Answer 5

Do not prescribe in patients with a history of macrolide hypersensitivity

Caution in patients with severe hepatic impairment and doses should be reduced in severe renal impairment

Question 6

What are the interactions with other drugs?

Answer 6

Erythromycin and clarithromycin (not azithromycin) inhibit CYP enzymes. Increases concentrations of drugs metabolised by this enzyme e.g. warfarin and statins

They should be prescribed with caution in people taking other drugs that prolong the QT or cause arrhythmias such as amiodarone, antipsychotics, quinine, quinolone antibiotics, and selective serotonin reuptake inhibitors (SSRIs).

Question 7

What are the names of drugs in this class?

Answer 7

clarithromycin, azithromycin, erythromycin